The Effect of Demonstrator Social Rank on the Attentiveness and Motivation of Pigs to Positively Interact with Their Human Caretakers

Abstract

In this study, we addressed the social attentiveness, as well as the phenomenon of social facilitation and inhibition in the context of a positive human–pig relationship. Specifically, we investigated whether the social rank of an experienced pig (termed “demonstrator”) has an effect on the attentiveness of the remaining pen mates (N = 40) when they observe the demonstrator being gently handled by a stockperson from behind an acrylic panel. We found that pigs preferentially attended to dominant demonstrators rather than subordinate demonstrators during their gentle handling sessions with the stockperson. Additionally, we also examined whether the presence of a demonstrator pig of different social rank, who previously established a positive relationship with the stockperson in presence of conspecifics, affects the behavior and motivation of their pen mates to positively interact with the stockperson. To test for the effect of the presence and demonstrator’s social rank on pen mate interactions with the stockperson, we evaluated the behavior of domestic pigs (N = 65) toward the stockperson using a human-approach test in their home-pen. Pigs showed a decrease in their motivation to positively interact with the stockperson when a socially dominant demonstrator was present, behaving similarly to animals receiving minimal human contact (control group). Overall, they exhibited a greater latency to physical contact, a lower acceptance of stroking, and spent more time looking at the stockperson compared to pigs exposed to subordinate demonstrators. Taken together, these findings expand our current understanding of pigs’ cognition and social behavior, and the nature of social attention bias in farm animals. Our findings indicate that positive handling of previously selected subordinate demonstrators seems to be the best strategy to reduce the level of fear in large groups of pigs.

Emulative learning of a two-step task in free-ranging domestic pigs

“…Schiel and Huber 2006 ; Voelkl et al 2006 ), adults have generally less opportunities to watch others from nearby, especially if they are of lower rank than the demonstrator. In pigs, dominant demonstrators seem to elicit stronger attention, but their presence during test situations rather inhibits the learned behaviour (Luna et al 2021b , but see 2021a ). In the present study, we tried to prevent this negative effect by always removing the demonstrator from the visual field of the observer during the test.…”

“…One such restriction poses the social structure in which pigs organize their group life, with an integral part being the dominance hierarchy and social relationships (Goumon et al 2020 ; Mcbride et al 1964 ). While dominant demonstrators seem to elicit stronger attention, their presence during test situations seems to rather inhibit learned behaviour (Luna et al 2021b , but see 2021a ). In comparison to conspecifics who may be seen as competitors for resources, adult pigs might rather benefit from a social demonstration of their human caregivers.…”